Boileb-plitg



F. E. KEY.

BOILER PLUG.

APPLICATION FILED mac. 3. 1915.

Patented Aug. 22, 1916.

FREDERICK E. KEY, 01* S TJLQUIS, MISSUUZELI.

BOILER-PLUG.

- Specification ofI-etters Patent.

Patented Aug. 22, 11916.

Application filed December 8, 1915. Serial Ito. 6%,794.

accompanying drawing, forming a part of this specification.

My invention relates to improvements in boiler-plugs, one of the objects being to produce a simple and inexpensive means for closing the hand holes of steam boilers.

With the foregoing and other objects in view the invention comprises the novel construction, combination and arrangement of parts hereinafter more specifically described and illustrated in the accompanying drawing, wherein is shown the preferred embodiment of the invention; however, it is to be understood that the invention comprehends changes, variations and modifications which come within the scope of the claims hereunto appended.

In accordance with the preferred form of the invention, the new article is a tapered hollow plug, closed at its inner end and open at its outer end to receive an expanding device. The plug is so formed that it may be easily and quickly applied to a boiler by hammering-the closed inner end of the plug, thereby forcing the tapered face of the plug into engagement with its seat. This tapered face is preferably so formed that the pressure of the boiler will tend to force the plug onto its seat. If leakage should occur at the plug, it may be tightened by expanding its tapered portion, the outer end of the plug being open'so that an expanding device may be easily applied thereto from the exterior of the boiler.

Figure I is an enlarged vertical section showing my expansible plug applied to a wall of a boiler, the expanding device being shown by dotted lines. Fig. II is a fragmentary view showing the expansible portion of theplug as it appears when expanded. Fig. III is a vertical section, on a reduced scale, showing a portion of the water leg of a boiler equipped with my improved plugs. Fig. IV is a detail view of one of the plugs shown in Fig. III.

The water leg, shown in Fig. III has an inner wall 1 to which the tubes 2 are applied, and an outer Wall 3 provided with hand holes through which the tubes may be inserted.

A designates plugs closing the hand holes in the wall 3. Each plug A is a hollow member closed at its inner end by a bowed wall I having a convex face which is exposed to the pressure in the boiler, a bowed wall of this kind being Well adapted to re sist such pressure. The outer end of each plug is open to receive an expanding device B, as shown by dotted lines in Fig. I. The hollow plug A has a. tapered, or conicocylindrical portion 5, which extends from the bowed wall 4 to the point X (Fig. I), and a reduced marginal portion 6 which .extends fromthe point X to the open end of the plugo This marginal portion 6 pro- ]ects from the wall 3 for a purpose which will be hereinafter described. The conicocylindrical portion 5 gradually decreases in diameter toward the open outer end of the plug, so that the pressure in the boiler will tend to force the plug onto its seat.

The plugs are inserted into the hand holes from the interior of the water leg, and then hammered on their closed inner ends l so as to force their conico-cylindrical portions into engagement with the wall 3. This will usually produce the desired tight joint, or seal, at the hand holes; however, if leakage should occur at any of the plugs they may be readily tightened by the expanding device.

The inner face of the expansible portion of the plug is smallest in diameter at the point S (Fig. I) said point being between the inner and outer margins of the conicocylindrical portion 5. When the expanding device is applied to a plug, it primarily engages the point S, and after the plug has been expanded it engages the wall 3 approximately as shown in Fig. II, a very tight joint being produced at the inner portion of the 'wall 3. The outer margin of the conico-cylindrical portion is reduced in thickness so that it is not forced into firm engagement with the wall 3 during the expanding operation. In removing the plugs from the wall 3, their extended marginal portions 6 at the exterior of the boiler are hammered to contract the expanded portions of the plugs, thus loosening the plugs so that they may be easily forced into the water leg.

I claim 1. As a new article of manufacture, a

hollow expansible boiler plug closed at one end and open at the opposite end to receive an expanding device, said boiler plug having a conico-cylindrical portion adapted to be forced onto the wall of the opening to which the plug is applied, the open end of the plug being adapted to enter said opening and the conico-cylindrical portion being so formed as to decrease in diameter toward the open end of the plug so that the plug, may be forced onto its seat by pressure on its closed end.

2. As a new article of manufacture, a hol low boiler plug closed at its inner end and open at its outer end to receive an expanding device, said hollow plug having a conico-cylindrical portion adapted to engage the wall of the opening to which the plug is applied, said conico-cylindrical portion being so formed as to decrease in diameter toward the open outer end of the plug so that outward pressure on the closed inner end of the plug will tend to force said conico-cylindrical portion onto the wall of said opening, the open outer end of the plug being adapted to pass through said opening, and said conico-cylindrical portion being adapted to be expanded to engage the wall of the opening. I

FREDERICK E. KEY. 

